The standard model of cosmology, rooted in Einstein's theory of general relativity, anticipates a specific growth rate for vast cosmic structures like galaxy clusters and filaments during the universe's expansion. However, new research from the University of Michigan has found that the growth of these structures is slower than predicted. They found that the growth of large cosmic structures has slowed down in recent eras of the universe, even though the overall expansion of the universe is accelerating.
This finding is significant because it challenges our current understanding of the universe. One possible explanation is that there is a new type of dark matter or dark energy that is suppressing the growth of large cosmic structures. Another possibility is that our understanding of gravity needs to be modified. The researchers' findings have been published in the journal Physical Review Letters. They say that their results could help to explain a major cosmic mystery known as the sigma-8 tension, which is a discrepancy between the predicted and observed values of a parameter that describes the distribution of matter in the universe.
According to Vice News, scientists led by Minh Nguyen, an astrophysicist and cosmologist at the University of Michigan, suggest that the growth of large-scale structures has been suppressed in the modern universe, even as the overall expansion of the universe has accelerated over time due to a mysterious force known as dark energy. The researchers concluded that some "cosmological tensions can be interpreted as evidence of growth suppression" and that the sigma-8 tension could be effectively resolved by their hypothesis.
"We did not set out to look for evidence of a late-time suppression specifically," said Nguyen in an email to Motherboard. "Our original intention was to see whether the history of the cosmic background expansion is consistent with the history of cosmic structure growth."
